The invention relates to a pan system for an engine housing structure of an internal combustion engine which has inner and outer pans with bottoms and upright walls which are placed inside one another and are trough-shaped in cross section. The inner pan accommodates lubricating oil of the internal combustion engine and the outer pan with the bottom and the upright walls runs at least in certain areas at a distance from the bottom and the walls of the inner pan so as to result in a channel-like intermediate space which contains cooling liquid of the internal combustion engine for affecting the temperature of the inner pan. Fins are provided on the inner walls and the outer walls, and the inner pan and the outer pan interact through the medium of a supporting system.
From EP 1 264 970 B1, an oil pan is known which is double-walled in certain areas and has an inner shell made of plastic and an outer shell made of metal. A coolant for the inner shell, which accommodates lubricating oil, flows in the space formed by the inner shell and the outer shell. The inner shell has supporting ribs which rest against a bottom and upright walls of the inner shell. Furthermore, cooling fins are provided on an outer side of a bottom of the outer shell. In addition, a heat exchanger, which affects the heat between coolant and ambient air, is integrated in the oil pan.
FR 2 721 975 A1 describes an oil pan which includes a plurality of cooling channels on its underside. The cooling channels are connected to the cooling circuit of an internal combustion engine and medium of the cooling circuit flows through them. Fins are provided in the oil pan and the cooling channels.
An internal combustion engine with a double wall can be seen from DE 31 42 327 A1. Its walls form a hollow space through which a coolant flows between inlet and outlet openings. The coolant flowing through the hollow space acts as a wall thickening for insulating air-borne noise.
The object of the invention is to design a pan system for an internal combustion engine for accommodating lubricating oil to be cooled by means of cooling liquid, which pan system can be combined with an engine housing of the internal combustion engine in a simply designed, functionally optimized and easy manner.
According to the invention, this object is achieved a pan system for an engine housing structure of an internal combustion engine which has two pans (inner and outer) with bottoms and upright walls which are placed inside one another and are trough-shaped in cross section. The inner pan accommodates lubricating oil of the internal combustion engine and the outer pan with the bottom and the upright walls runs at least in certain areas at a distance from the bottom and the walls of the inner pan so as to result in a channel-like intermediate space which contains cooling liquid of the internal combustion engine for affecting the temperature of the inner pan. Fins are provided on the inner walls and the outer walls, and the inner pan and the outer pan interact through the medium of a supporting system. The inner pan and the outer pan are made of metallic material and the inner pan is provided at least on one inner side of the bottom and the upright walls with a cooling fin system for optimizing the heat transfer. The supporting system is effective between the bottoms of the inner pan and the outer pan. The upright walls of the inner pan and of the outer pan are connected to the engine housing structure.
The advantages mainly achieved with the invention are to be seen in that the inner wall and the outer wall of the pan system can be constituted in the intended manner with defined design effort. In doing so, the inner walls and the outer walls are made of metal, preferably of lightweight metal, and have an advantageous strength and thermal conductivity. Furthermore, the particularly ingenious cooling fin system, above all on the bottom and the upright walls of the inner wall, enables an optimized heat transfer between the inner pan, which is exposed to the coolant of the internal combustion engine, and the lubricating oil of the the internal combustion engine. The supporting system between the bottoms of the inner pan and the outer pan and also the chosen connection of the upright walls of the latter mentioned pans to the engine housing structure of the internal combustion engine are also to be emphasized in this regard. For appropriate applications, the cooling fin system can also be provided on the outer side of the upright walls of the inner pan.
The supporting system is therefore exemplary in design, as it has a supporting pin with a mounting bolt on the bottom of the inner pan which rests on a mounting bush of the bottom of the outer pan, wherein the mounting bolt is actively connected to a hole in the mounting bush. The supporting system is functionally expanded in that the mounting bolt is provided with an oil drain screw. Cleverly solved from a design point of view is that free ends of the inner pan and the outer pan are formed as supports which interact with counter supports of a connecting housing of the engine housing structure under defined supporting load. The last solution is further optimized in that the supports and the counter supports are bounded by a common plane between the inner pan and the outer pan or the connecting housing.
The cooling fin system sets standards in that it includes a plurality of bottom cooling fins, which are uniformly distributed for example, on an inner side of the bottom as well as wall cooling fins on an inner side of the upright walls of the of the inner pan. The bottom cooling fins and the wall cooling fins are aligned substantially perpendicular to the bottom and the upright walls of the inner pan. At the same time, the fact that at least one of the bottom cooling fins extends over a defined partial height of a total height of the upright walls of the inner pan contributes to the particular efficiency of the cooling fin system. This is assisted in that the partial height is defined, for example, by the product 0.5×total height of the upright walls of the inner pan. Improving the effect is also that, on the one hand, at least one part of the wall cooling fins extends approximately over the partial height of the bottom cooling fins and, on the other hand, that a first length of the wall cooling fins on the outer side of the upright walls of the inner pan is approx. 12 to 15 mm. Also contributing to efficiency optimization are that, on the one hand, a second length of the wall cooling fins on the inner side of the upright walls of the inner pan is defined by the factor 0.8 to 0.9× the first length and, on the other hand, the distance at least between a part of the bottom cooling fins and the wall cooling fins is defined by the product 2× the first length of the wall cooling fins on the outer side of the upright walls of the inner pan. Finally, it is also of advantage when the thickness of at least one part of the bottom and wall cooling fins is between 1.5 and 2.5 mm.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.